1. Field of the Invention
The present invention generally relates to the treatment of a dermatological condition and, more specifically, to the treatment of psoriasis, by topical application of a composition comprising a peptide copper complex.
2. Description of the Related Art
Psoriasis is a chronic disease characterized by raised red, scaly, and often pruritic plaques. These plaques can appear anywhere on the skin. Psoriasis is a very visible skin condition that has a high impact on the quality of life of the patient.
Three basic treatments are currently used for psoriasis: 1) applying a topical agent, 2) using phototherapy, and 3) applying systemic agents. Applying a topical agent is typically the first approach to treating psoriasis. Topical agents include corticosteroids, coal tar, anthralin, calcipotriene, and tazarotene. The treatment of choice for providing symptomatic relief entails the topical application of corticosteroids. All topical steroids have anti-inflammatory, anti-pruritic, and vasoconstrictive effects. However, their long-term use is often accompanied by loss of effectiveness.
Topical coal tar contains more than 10,000 different chemical substances. The exact mechanism of action thereof is unknown. The most common coal tar treatment protocol (the Goeckermann method, which also uses UV phototherapy) involves almost a month of messy topical treatments at a day treatment center. Although this method has a high rate of success in clearing skin, it is relatively expensive and time-consuming. Anthralin is a synthetic derivative of a tree bark extract and is a cellular antiproliferative agent that decreases the rate of epidermal cell growth. Although anthralin is considered one of the most effective agents available for treating psoriasis, it is not in widespread use because of its high potential to cause irritation and staining of the skin.
Calcipotriene is a synthetic vitamin D-3 analog that regulates skin cell production. It is not in widespread use, however, because it is expensive and dosage is limited due to the risk of irritation and vitamin D toxicity. Tazarotene is a retinoid derivative that has been used to topically treat psoriasis. However, it often causes irritation and, thus, is typically used in conjunction with topical steroid treatments. For plaque psoriasis, retinoids are used in combination with ultraviolet phototherapy to minimize the dosage thereof that is required. The utility of such methods is limited by the side effects and precautions that are generally associated with retinoids, as would be appreciated by one skilled in the art.
Phototherapy is generally used only in the presence of extensive, widespread disease. Resistance to other topical treatments is another indication for phototherapy. There are two main forms of phototherapy, UVB and PUVA phototherapy. UVB, or Ultraviolet B, phototherapy uses light having a wavelength in the range of 290–320 nm. Such phototherapy is usually combined with one or more topical treatments including: topically applying coal tar, followed by using UVB (the aforementioned Goeckerman method); using a coal tar bath, followed by UVB, and then followed by topically applying anthralin (the Ingram method); or using UVB in combination with topically applying corticosteroids, calcipotriene, tazarotene, or simply bland emollients. A major drawback of such methods is the long duration thereof and accessibility to UVB equipment.
PUVA uses the photosensitizing drug methoxsalen (8-methoxypsoralens) in conjunction with UVA light (wavelengths in the 320–400 nm range). PUVA interferes with DNA synthesis (methoxsalen binds covalently to pyrimidine bases in DNA), decreases cellular proliferation, and induces apoptosis of cutaneous lymphocytes leading to localized immunosuppression. Adverse effects associated with both of these treatments include nausea, pruritus, burning, photo damage to the skin and increased risk of skin cancer.
Systemic psoriasis treatment is usually initiated only after both topical treatment and phototherapy have failed, or for patients with very active psoriatic arthritis. The main agents available are the immunomodulators Methotrexate and Cyclosporine, and the oral retinoid Acitretin, and new biological agents. For example, recent new proposed treatments involve recombinant human cytokines, growth factors, or monoclonal antibodies and fusion proteins thereof (Wons, V. K., Croce, C. D. and Lebwohl, M., Cosmetic Dermatology 15(11) 33–34 (2002)).
Methotrexate is a folic acid antagonist that inhibits DNA synthesis in tissues with high rates of turnover, such as psoriatic plaques, and is immunosuppressive to mononuclear cells in the skin, blood, and lymphatics. Methotrexate has toxic effects on hematologic, renal, GI, pulmonary, and neurologic systems. Cyclosporine inhibits production of interleukin-2, the cytokine responsible for inducing T-Cell proliferation. Psoriasis skin lesions can recur within days to weeks after this systemic treatment is stopped. Adverse effects include hypertension, impaired renal function, and an increased risk of cancer. Acitretin is a second generation oral retinoid. The use of oral retinoid therapy has shown limited efficacy for chronic stable plaque psoriasis.
Thus, while there are a number of treatments for psoriasis currently available, they all are accompanied by various side effects, high costs, and long complicated treatment protocols. Accordingly, there remains a need in the art for more effective and otherwise improved methods for treating dermatological conditions related to psoriasis by, for example, topically applying compositions, having a desired degree of effectivity, to areas of skin of a patient in need thereof. The present invention fulfills this need and provides further related advantages.